Fatty Acid Binding Protein 4 Is Associated with Carotid Atherosclerosis and Outcome in Patients with Acute Ischemic Stroke

BACKGROUND AND PURPOSE: Fatty acid binding protein 4 (FABP4) has been shown to play an important role in macrophage cholesterol trafficking and associated inflammation. To further elucidate the role of FABP4 in atherogenesis in humans, we examined the regulation of FABP4 in carotid atherosclerosis and ischemic stroke. METHODS: We examined plasma FABP4 levels in asymptomatic (n = 28) and symptomatic (n = 31) patients with carotid atherosclerosis, as well as in 202 subjects with acute ischemic stroke. In a subgroup of patients we also analysed the expression of FABP4 within the atherosclerotic lesion. In addition, we investigated the ability of different stimuli with relevance to atherosclerosis to regulate FABP4 expression in monocytes/macrophages. RESULTS: FABP4 levels were higher in patients with carotid atherosclerosis, both systemically and within the atherosclerotic lesion, with particular high mRNA levels in carotid plaques from patients with the most recent symptoms. Immunostaining of carotid plaques localized FABP4 to macrophages, while activated platelets and oxidized LDL were potent stimuli for FABP4 expression in monocytes/macrophages in vitro. When measured at the time of acute ischemic stroke, high plasma levels of FABP4 were significantly associated with total and cardiovascular mortality during follow-up, although we did not find that addition of FABP4 to the fully adjusted multivariate model had an effect on the prognostic discrimination for all-cause mortality as assessed by c-statistics. CONCLUSIONS: FABP4 is linked to atherogenesis, plaque instability and adverse outcome in patients with carotid atherosclerosis and acute ischemic stroke

DNA glycosylase Neil3 regulates vascular smooth muscle cell biology during atherosclerosis development.

BACKGROUND AND AIMS: Atherogenesis involves a complex interaction between immune cells and lipids, processes greatly influenced by the vascular smooth muscle cell (VSMC) phenotype. The DNA glycosylase NEIL3 has previously been shown to have a role in atherogenesis, though whether this is due to its ability to repair DNA damage or to other non-canonical functions is not yet clear. Hereby, we investigate the role of NEIL3 in atherogenesis, specifically in VSMC phenotypic modulation, which is critical in plaque formation and stability. METHODS: Chow diet-fed atherosclerosis-prone Apoe-/- mice deficient in Neil3, and NEIL3-abrogated human primary aortic VSMCs were characterized by qPCR, and immunohistochemical and enzymatic-based assays; moreover, single-cell RNA sequencing, mRNA sequencing, and proteomics were used to map the molecular effects of Neil3/NEIL3 deficiency in the aortic VSMC phenotype. Furthermore, BrdU-based proliferation assays and Western blot were performed to elucidate the involvement of the Akt signaling pathway in the transdifferentiation of aortic VSMCs lacking Neil3/NEIL3. RESULTS: We show that Neil3 deficiency increases atherosclerotic plaque development without affecting systemic lipids. This observation was associated with a shift in VSMC phenotype towards a proliferating, lipid-accumulating and secretory macrophage-like cell phenotype, without changes in DNA damage. VSMC transdifferentiation in Neil3-deficient mice encompassed increased activity of the Akt signaling pathway, supported by cell experiments showing Akt-dependent proliferation in NEIL3-abrogated human primary aortic VSMCs. CONCLUSIONS: Our findings show that Neil3 deficiency promotes atherosclerosis development through non-canonical mechanisms affecting VSMC phenotype involving activation of the Akt signaling pathway

Neil3-dependent base excision repair regulates lipid metabolism and prevents atherosclerosis in Apoe-deficient mice

Increasing evidence suggests that oxidative DNA damage accumulates in atherosclerosis. Recently, we showed that a genetic variant in the human DNA repair enzyme NEIL3 was associated with increased risk of myocardial infarction. Here, we explored the role of Neil3/NEIL3 in atherogenesis by both clinical and experimental approaches. Human carotid plaques revealed increased NEIL3 mRNA expression which significantly correlated with mRNA levels of the macrophage marker CD68. Apoe−/−Neil3−/− mice on high-fat diet showed accelerated plaque formation as compared to Apoe−/− mice, reflecting an atherogenic lipid profile, increased hepatic triglyceride levels and attenuated macrophage cholesterol efflux capacity. Apoe−/−Neil3−/− mice showed marked alterations in several pathways affecting hepatic lipid metabolism, but no genotypic alterations in genome integrity or genome-wide accumulation of oxidative DNA damage. These results suggest a novel role for the DNA glycosylase Neil3 in atherogenesis in balancing lipid metabolism and macrophage function, potentially independently of genome-wide canonical base excision repair of oxidative DNA damage

Lack of effects of a single high-fat meal enriched with vegetable n-3 or a combination of vegetable and marine n-3 fatty acids on intestinal peptide release and adipokines in healthy female subjects

Peptides released from the small intestine and colon regulate short-term food intake by suppressing appetite and inducing satiety. Intake of marine omega-3 (n-3) fatty acids from fish and fish oils is associated with beneficial health effects, whereas the relation between intake of the vegetable n-3 fatty acid α-linolenic acid and diseases is less clear. The aim of the present study was to investigate the postprandial effects of a single high-fat meal enriched with vegetable n-3 or a combination of vegetable and marine n-3 fatty acids with their different unsaturated fatty acid composition on intestinal peptide release and the adipose tissue. Fourteen healthy lean females consumed three test meals with different fat quality in a fixed order. The test meal consisted of three cakes enriched with coconut fat, linseed oil and a combination of linseed and cod liver oil. The test days were separated by two weeks. Fasting and postprandial blood samples at three and six hours after intake were analysed. A significant postprandial effect was observed for cholecystokinin, peptide YY, glucose-dependent insulinotropic polypeptide, amylin and insulin which increased, while leptin decreased postprandially independent of the fat composition in the high-fat meal. In conclusion, in healthy, young, lean females, an intake of a high-fat meal enriched with n-3 fatty acids from different origin stimulates intestinal peptide release without any difference between the different fat compositions

Matrix metalloproteinase 7 is associated with symptomatic lesions and adverse events in patients with carotid atherosclerosis.

BACKGROUND: Atherosclerosis is a major cause of cerebrovascular disease. Matrix metalloproteinases (MMPs) play an important role in matrix degradation within the atherosclerotic lesion leading to plaque destabilization and ischemic stroke. We hypothesized that MMP-7 could be involved in this process. METHODS: Plasma levels of MMP-7 were measured in 182 consecutive patients with moderate (50-69%) or severe (≥70%) internal carotid artery stenosis, and in 23 healthy controls. The mRNA levels of MMP-7 were measured in atherosclerotic carotid plaques with different symptomatology, and based on its localization to macrophages, the in vitro regulation of MMP-7 in primary monocytes was examined. RESULTS: Our major findings were (i) Patients with carotid atherosclerosis had markedly increased plasma levels of MMP-7 compared to healthy controls, with particularly high levels in patients with recent symptoms (i.e., within the last 2 months). (ii) A similar pattern was found within carotid plaques with markedly higher mRNA levels of MMP-7 than in non-atherosclerotic vessels. Particularly high protein levels of MMP-7 levels were found in those with the most recent symptoms. (iii) Immunhistochemistry showed that MMP-7 was localized to macrophages, and in vitro studies in primary monocytes showed that the inflammatory cytokine tumor necrosis factor-α in combination with hypoxia and oxidized LDL markedly increased MMP-7 expression. (iv) During the follow-up of patients with carotid atherosclerosis, high plasma levels of MMP-7 were independently associated with total mortality. CONCLUSION: Our findings suggest that MMP-7 could contribute to plaque instability in carotid atherosclerosis, potentially involving macrophage-related mechanisms

Omicron Variant Generates a Higher and More Sustained Viral Load in Nasopharynx and Saliva Than the Delta Variant of SARS-CoV-2

The Omicron variant of SARS-CoV-2 spreads more easily than earlier variants, possibly as a result of a higher viral load in the upper respiratory tract and oral cavity. Hence, we investigated whether the Omicron variant generates a higher viral load than that of the Delta variant in saliva and nasopharynx. Both specimens were collected from 52 Omicron and 17 Delta cases at two time points one week apart and analyzed by qRT-PCR. Viral load was measured as 10 log RNA genome copies per 1000 human cells according to the WHO reference standard. We found that Omicron cases carried a higher viral load and had more sustained viral shedding compared to the Delta cases, especially in the nasopharynx

Increased levels of CCR7 ligands in carotid atherosclerosis: different effects in macrophages and smooth muscle cells

AIM: The homeostatic chemokines CCL19 and CCL21 and their receptor CCR7 have recently been linked to atherogenesis. We investigated the expression of CCL19/CCL21/CCR7 in carotid atherosclerosis as well as the ability of these chemokines to modulate lipid accumulation in macrophages and vascular smooth muscle cell (SMC) phenotype.Methods and ResultsOur major findings were: (i) Patients with carotid atherosclerosis (n=158) had increased plasma levels of CCL21, but not of CCL19, compared to controls (n=20), with particularly high levels in symptomatic (n=99) as compared with asymptomatic (n=59) disease. (ii) Carotid plaques showed markedly increased mRNA levels of CCL21 and CCL19 in symptomatic (n=14) as compared with asymptomatic (n=7) patients, with CCR7 localized to macrophages and vascular SMC (immunohistochemistry). (iii) In vitro, CCL21, but not CCL19, increased the binding of modified LDL and promoted lipid accumulation in THP-1 macrophages. (iv). CCL19, but not CCL21, increased proliferation and release and activity of matrix metalloproteinase (MMP) 1 in vascular SMC. (v). The differential effects of CCL19 and CCL21 in macrophages and SMC seem to be attributable to divergent signaling pathways, with CCL19-mediated activation of AKT in SMC and CCL21-mediated activation of extracellular signal-regulated kinase 1/2 in macrophages. CONCLUSION: CCL19 and CCL21 are up-regulated in carotid atherosclerosis. The ability of CCL21 to promote lipid accumulation in macrophages and of CCL19 to induce proliferation and MMP-1 expression in vascular SMC could contribute to their pro-atherogenic potential

Increased expression of NAMPT in PBMC from patients with acute coronary syndrome and in inflammatory M1 macrophages

AbstractAimThe aim of the present study were to elucidate the role of NAMPT in atherosclerosis, by examine NAMPT expression in peripheral blood mononuclear cells (PBMC) in patients with coronary artery disease (CAD) and healthy controls and by examining the regulation and effect of NAMPT on macrophage polarization, hypothesizing that it could influence the polarization to inflammatory and resolving macrophages.Method and ResultsWe analyzed RNA levels of NAMPT in PBMC from CAD and healthy controls and found NAMPT to be increased in PBMC from patients with acute coronary syndrome (n = 39) compared to healthy controls (n = 20) and patients with stable CAD (n = 22). Within the PBMC NAMPT was correlated to several inflammatory cytokines and the antioxidant enzyme superoxide dismutase 2. In vitro cell experiments revealed that NAMPT is increased both intracellular and extracellular in inflammatory M1 macrophages compared to in anti-inflammatory M2 macrophages. In addition, inhibiting NAMPT enzymatic activity inhibited M1 polarization in macrophages.ConclusionBased on our in vivo and in vitro findings we suggest that NAMPT could contribute to systemic and plaque inflammation in atherosclerotic disorders at least partly through effect on macrophages